<!DOCTYPE html>
<html>
  <head>
    <style>
      canvas {
          background-color: rgba(0, 0, 0, 1);
      }

      .hidden {
          visibility: hidden;
      }

      .visible {
          visibility: visible;
      }
    </style>

    <script>
      function drawCanvas(canvasID, clearColor)
      {
          var theCanvas = document.getElementById(canvasID);
          var glContext = theCanvas.getContext("webgl");
          glContext.clearColor(clearColor[0], clearColor[1], clearColor[2], clearColor[3]);
          glContext.clear(glContext.COLOR_BUFFER_BIT);
      }

      function init()
      {
          drawCanvas("topGL", [0, 0.5, 0, 1]);
          drawCanvas("bottomGL", [1, 0, 0, 1]);
      }
    </script>
  </head>

  <body onload="init()">
    <!-- Tests CSS visibility flag for WebGL layers. -->
    <!-- Pixel test only. Only the green webGL canvas should be visible. The red one should be hidden. -->
    <div><canvas id="topGL" class="visible" width="150" height="150"></canvas></div>
    <div><canvas id="bottomGL" class="hidden" width="150" height="150"></canvas></div>
  </body>
</html>
